Smaller sailing and motor boats typically deploy fenders when mooring at jetties or against other boats to protect the boat or boats from impact and abrasion damage. The fenders are usually formed of resilient plastics materials and may be hollow to allow for some deformation when absorbing the energy of an impact, for example. The fenders are commonly deployed, only when needed, by tying each one in place and placing them to hang at the side of the boat. On smaller boats in particular this operation can be difficult, particularly in choppy sea conditions, running the risk of the person failing overboard. There is therefore a need for a system which enables fenders to be automatically deployed when needed and automatically retracted when not needed.
JP11301586 discloses an air bag device for absorbing impact shock. A number of the devices are located around the hull of the boat and are inflated by compressed air when bringing the boat alongside a pier, quay or another boat. The air bags are held within containers attached to the side of the boat, and when deflated are intended to retract into the containers, which are provided with hinged covers. A problem with this arrangement is that it depends on the air bags being elastic so as to return to the original small size when deflated. This would require the bags to be formed of relatively thin material to allow the desired degree of stretching during inflation, and high pressure compressed air would be required to inflate them. As a result, there would be a considerable risk of explosive deflation if the bag is over-inflated, punctured or suffers excessive compressive force during impact. This could result in risk to the occupants of the boat of injury from high velocity fragments of the air bag, and would render the boat itself unprotected by fenders and therefore at risk of impact or abrasive damage.
In order to achieve sufficient protection without the need for a high degree of inflation, the fenders would need to be made larger in the uninflated configuration, and this would lead to an unacceptable effect on the clean lines of the boat, or would take up space within the boat hull.
GB2381845A and DE29704772U1 both disclose an inflatable fender for a boat, comprising an enclosure mounted on or in the boat hull and connectible to a fluid supply, an inflatable flexible member in the form of a flat tube rolled around a first roller mounted within the enclosure and the fluid supply being connectable to the tube to inflate the tube, the tube extending from the enclosure when inflated, and drive means being provided to rotate the roller to retract the tube when not required, the fluid supply being arranged to allow the fluid to withdraw from the tube as the tube is rolled on to the roller.